Vehicular camera and lens assembly

ABSTRACT

A process for providing a vehicular camera suitable for vehicular use includes providing a front camera housing having a lens assembly disposed thereat and providing an imager disposed on a printed circuit board. An adhesive is disposed in its uncured state between the front camera housing and the printed circuit board. The front camera housing and said printed circuit board are adjusted relative to each other to achieve optical center-alignment and focusing of the lens optics relative to the imager. The adhesive is initially cured from its uncured state to an initially-cured state in an initial radiation curing process that includes exposure to UV light for a first time period. After optical center-alignment and focusing, the adhesive is further cured from the initially-cured state to a further more cured state in a secondary curing process undertaken for a second time period that is longer than the first time period.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/033,964, filed Sep. 23, 2013, now U.S. Pat. No. 9,338,334, which is acontinuation of U.S. patent application Ser. No. 13/260,400, filed Sep.26, 2011, now U.S. Pat. No. 8,542,451, which is a 371 national phasefiling of PCT Application No. PCT/US10/28621, filed Mar. 25, 2010, whichclaims the benefit of U.S. provisional application Ser. No. 61/232,544,filed Aug. 10, 2009, and U.S. provisional application Ser. No.61/163,240, filed Mar. 25, 2009, the contents of both of which areincorporated herein.

FIELD OF THE INVENTION

The invention relates to vehicular cameras, and more particularly, tolow cost construction and assembly of such cameras.

BACKGROUND OF THE INVENTION

Vehicular cameras are used for a variety of purposes, such as to assista driver in avoiding obstacles behind a vehicle when backing up, and todetect imminent collisions ahead of the vehicle when driving forward. Avehicular camera includes a lens that focuses video input on an imagesensor provided on an imager. In general, the position of the lensrelative to the image sensor can impact the quality of the video inputreceived by the image sensor. For example, if the lens is positionedsuch that the video input is not in focus, then the video informationpassed to the driver may be blurry, and other vehicular systems, such asa collision detection system for example, may not function as well asthey otherwise could. As the size of the camera is reduced, thepositioning of the lens relative to the image sensor may be relativelymore critical, at least because small variations in position can resultin relatively large changes in angular offset. Therefore, thepositioning of the lens relative to the image sensor may be particularlycritical for vehicular rearview cameras. Furthermore, it is importantthat the camera be capable of holding the lens in position over aselected period of time under certain operating conditions, so that theperformance of the camera is maintained over a useful operating life.

Several aspects of the camera may contribute to the overall tolerance inthe position of the lens relative to the image sensor. For example, forlenses and lens holders that are threaded, the threaded connectiontherebetween has a tolerance associated with it. The angle of cast ofthe lens holder has a tolerance associated with it. The position of theimager has a tolerance associated with it.

It is desirable to provide a more integrated, lower cost camera assemblywith means for positioning the lens relative to the imager withintolerance.

SUMMARY OF THE INVENTION

In one aspect, the invention is directed to a vehicular camera having alens that is mounted to a lens holder and is held in position by aselected adhesive. The adhesive is capable of being initially curedrelatively quickly by exposure to UV light for supporting the lensrelative to the lens holder. The adhesive is further capable of beingcured by exposure to a secondary curing condition, such as by exposureto heat, to achieve a fully cured strength, which may take a relativelylonger period of time, such as minutes or hours. By providing anadhesive that is initially curable quickly but that reaches a selectedfully cured strength and selected performance characteristics, thecamera lends itself to having the lens positioned by a robot and thenhaving the adhesive cured quickly to fix the position of the lens sothat the camera can be transferred from the robot to a curing fixturefor exposure to the secondary curing condition to fully cure theadhesive. Thus, the robot, which may be a relatively expensive componentof a system used to manufacture the camera, can be used to adjust thelens of another camera, which may then be transferred to another curingfixture.

In a particular embodiment, the invention is directed to a vehicularcamera including a lens, a lens holder, and an imager. The lens isconnected to the lens holder by an adhesive. The adhesive is curable byUV light sufficiently to support the lens in the lens holder. Theadhesive is further curable to a fully cured strength when exposed to asecondary curing step. The adhesive is configured to provide at least aselected strength of bond between the lens and lens holder when exposedto at least one selected operating condition for a selected period oftime. The imager includes an image sensor positioned for receiving videoinput from the lens. The camera is configured to transmit to at leastone other vehicular device signals relating to the video input receivedby the imager. In a further particular embodiment, the adhesive may bereferred to as adhesive AD VE 43812 by Delo Industrial Adhesives ofWindach, Germany.

In another aspect, a vehicular camera is provided which includes a firstcamera housing having an integrated barrel portion for holding opticalcomponents; optical components mounted in the barrel portion so as toform a lens; a retainer cap mounted to the barrel portion for containingand vertically positioning the optical components in the barrel portion;imaging circuitry including an image sensor positioned for receivingoptical images from the lens; and a second camera housing, connected tothe first camera housing so as to encase the imaging circuitry.

In another aspect, a vehicular camera is provided which includes a lensincluding a lens barrel holding optical components therein; an imagerfor receiving images from the lens; and a housing encasing the imagerand a portion of the lens barrel. The lens barrel includes a feature forguiding and seating a periphery of the lens barrel onto the surface ofthe imager. Means such as adhesive or solderable retainer pins areprovided for securing the lens barrel to the imager. And means areprovided for ensuring focus between the lens and imager. The lens barrelmay also be integrated with at least a portion of the housing.

In another aspect, a vehicular camera is provided which includes a lensincluding a lens barrel holding optical components therein; an imagerfor receiving images from the lens; a printed circuit board (PCB) formounting the imager; a lens holder for mounting the lens barrel, thelens holder including a feature for guiding the lens barrel transverselyrelative to the imager; set screws for mounting the PCB to the lensholder; and means such as compressive gaskets, wave washers or lockwasher in combination with the set screws to hold the axial position ofthe PCB and imager relative to the lens.

In another aspect, a vehicular camera is provided which includes a firstcamera housing having an integrated barrel portion for holding opticalcomponents; optical components mounted in the barrel portion so as toform a lens; an imager for receiving images from the lens; a printedcircuit board (PCB) for mounting the imager; and a second camera housingto which the PCB is mounted, where the first and second camera housingsin combination encasing the imager and PCB. The first and second camerahousing are secured via UV-cured adhesive that is cured with UV lightonly after the position of the second camera housing relative to thefirst camera housing is set to bring the lens in focus and opticallycenter-aligned with the imager.

In another aspect, a vehicular camera is provided which includes acamera housing having an integrated barrel portion for holding opticalcomponents; optical components mounted in the barrel portion so as toform a lens; an imager for receiving images from the lens; a printedcircuit board (PCB) for mounting the imager. The PCB is secured to thecamera housing by a UV-cured adhesive that is cured only after theposition of PCB relative to the housing is set to bring the lens infocus and optically center-aligned with the imager.

In another aspect, a vehicular camera is provided which includes a lensincluding a lens barrel holding optical components therein; an imagerfor receiving images from the lens; and a printed circuit board (PCB)for mounting the imager. The lens barrel is directly secured to theimager by a transparent UV-cured adhesive fixing the lens barrel to atleast one of the imager and the PCB. The adhesive is cured only afterthe position of lens barrel relative to the imager is set to bring thelens in focus and optically center-aligned with the imager.

In another aspect, an improved vehicular camera system is provided wherethe lens resolution is selected to meet but not substantially exceed aresolution determined from the size of a display, a distance between anobserver and the display, a selected point on a contrast sensitivityfunction, and the size of an imager sensing surface.

In another aspect, an improved vehicular camera system is provided wherewherein the lens omits achromatic lenses and employs digital chromaticcorrection based on a predetermined chromatic aberration measurement.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be described by way of example only withreference to the attached drawings in which:

FIG. 1 is an exploded perspective view of a vehicular camera inaccordance with an first embodiment of the invention wherein a lensbarrel is adhesively secured to a lens holder via a UV-curable adhesive;

FIG. 2 is a cutaway side view of the vehicular camera shown in FIG. 1,in an assembled state;

FIG. 3 is a schematic cross-sectional view of a variant of the firstembodiment;

FIG. 4 is a cross-sectional view of a prior art lens;

FIG. 5 is a schematic cross-sectional view of a second embodiment of theinvention wherein a lens barrel is integrated with a camera lens holder;

FIG. 6 is a schematic cross-sectional view of a third embodiment of theinvention wherein a lens barrel is dropped on a surface of an imager;

FIG. 6A is a detail view of a portion of FIG. 6;

FIG. 7 is a schematic cross-sectional view of a variant of the thirdembodiment;

FIG. 8 is a detail cross-sectional view of the third embodiment;

FIG. 9 a schematic cross-sectional view of a fourth embodiment of theinvention wherein a lens is focused by PCB mounting screws;

FIG. 10 is a schematic cross-sectional view of the fourth embodimentincluding a back housing;

FIG. 11 is a schematic cross-sectional view of a fifth embodiment of theinvention wherein a lens is focused by the selective positioning ofcamera front and back housings;

FIG. 12 is a schematic cross-sectional view of a variant of the fifthembodiment;

FIG. 13 is a schematic cross-sectional view of a variant of the fifthembodiment, wherein a PCB is selectively positioned;

FIG. 14 is a schematic cross-sectional view of a sixth embodiment of theinvention wherein a lens is focused by directly attaching a lens to animager through a transparent adhesive;

FIG. 15 is a graph of a contrast sensitivity function; and

FIG. 16 is a graph of an example of lens chromatic aberration.

DETAILED DESCRIPTION OF THE INVENTION Embodiment 1 Use of UV-CurableAdhesive to Mount Lens to Holder

FIG. 1 shows an exploded view of a vehicular camera 10 in accordancewith a first embodiment of the invention. The vehicular camera 10includes an imager 20, a lens holder such as a front camera housing 14and a lens 16. The vehicular camera 10 may include other components suchas additional circuitry for processing the video input received by theimager 20, e.g., circuitry for providing graphic overlay to the videoinput. The vehicular camera 10 may further be configured to transmit thevideo input to other vehicular devices, such as a display controller(not shown) for a cabin-mounted display (not shown).

The imager 20 may be a charge-coupled device (CCD) or a complimentarymetal-oxide semiconductor (CMOS) sensor. Referring additionally to FIG.2, the imager 20 is mounted to a printed circuit board (PCB) 12. Theimager 20 is positioned to receive optical images from the lens 16. Inthe exemplary embodiment shown in FIG. 1, the imager 20 is connected tothe lens holder 14 by a plurality of threaded fasteners 22.

The lens 16 is mounted to the lens holder/front camera housing 14 at aselected position for focusing video input onto the sensing surface ofthe imager 20. The lens 16 may be any suitable type of lens known in theart. The lens 16 may have an exterior surface 24 that is configured tobe received in a cylindrical aperture 26 having an aperture wall 28 onthe lens holder/front camera housing 14. The exterior surface 24 and theaperture wall 28 may have a selected amount of clearance therebetween,shown by a gap G. An adhesive 30 is provided for holding the lens 16 ina specific position relative to the lens holder/front camera housing 14.More particularly, the adhesive 30 may be applied between a first axialface 32 on the lens holder/front camera housing 14, and a second axialface 34 on the lens 16.

The position of the lens 16 relative to the imager 20 impacts the degreeof focus present in the optical images received by the imager 20 andthus the performance of the camera 10 and the optical alignment of theoptical image on the imager.

To control the position of the lens 16, a positioning system (not shown)may be provided that includes a robot (not shown). The robot holds andadjusts the position of the lens 16 relative to the lens holder/frontcamera housing 14 until a target object appears in suitable focus and ata suitable position on the imager 20, prior to hardening of the adhesive30. The adjustment of the lens 16 relative to the lens holder/frontcamera housing 14 is facilitated by providing the selected amount ofclearance between the exterior surface 24 of the lens 16 and theaperture wall 28 of the lens holder/front camera housing 14.Additionally, the thickness of the layer of adhesive 30 between the lens16 and lens holder/front camera housing 14 may be selected to provide asuitable amount of relative angular adjustment between the lens 16 andlens holder 14/front camera housing. The thickness of the layer ofadhesive may be approximately 0.75 mm prior to adjustment of the lens16.

Once the lens 16 has been suitably positioned by the robot, the adhesive30 is initially cured by exposure to UV light while the robot holds thelens 16 in position. The UV light may be provided from a plurality of UVsources about the periphery of the camera 10. The initial curing of theadhesive 30 may result in the adhesive being strong enough to hold thelens 16 in the lens holder/front camera housing 14 without needing therobot to grip the lens 16, and may take less than 7 seconds. However,the lens 16 may be susceptible to movement if it incurs a relativelysmall disturbance at this stage. After the initial curing, the camera 10may be placed by the robot relatively gently on a conveyor (not shown)and moved to a UV curing station (not shown) for a further UV curingperiod, such as, for example, 25 seconds. Another UV curing station (notshown) may optionally be provided to further cure the adhesive 30 foranother period, such as 25 seconds, after the camera 10 leaves the firstUV curing station. Subsequent to the UV curing, the camera 10 may betransferred to another curing station where the adhesive 30 can bethermally cured, or may be cured by exposure to some other secondarycuring condition, to achieve its fully cured strength so that it canhold the lens 16 in position during use on a vehicle. The step ofinitially curing the adhesive 30 using UV light may be relativelyinstantaneous. This step of thermally curing the adhesive may takeseveral minutes or hours. As an additional or alternative curingmeasure, the adhesive 30 may be moisture cured.

Providing an adhesive 30 that has an initial curability by UV light isadvantageous in that the robot is not needed to hold the lens 16 inposition over the period of time that it would take for the secondarycuring condition to sufficiently harden the adhesive 30 to beself-supporting. Once the camera 10 is transferred from the robot to thecuring fixture, the robot can be used for the positioning of anotherlens 16 in another lens holder 14/front camera housing. Because the taskof positioning the lens 16 and initially curing the adhesive 30 using UVlight can take less time than fully thermally curing of the adhesive 30,a single robot can feed cameras 10 with initially cured lenses to aplurality of curing fixtures, thereby providing the capability ofachieving a relatively high rate of production per robot.

Once fully cured, the adhesive 30 may be capable of holding the lens 16in position with at least a selected strength of bond between the lens16 and lens holder/front camera housing 14 under one or more selectedoperating conditions. For example, the adhesive 30 may be capable ofholding the lens 16 in position after a selected time period of 1000hours of exposure to a selected temperature of 85 degrees Celsius andoptionally a humidity of approximately 85%. Any of the aforementionedselected values may be selected to suit the particular environment thatthe camera 10 is expected to experience during use. The selected timeperiod may, for example, be some other time period, such asapproximately 1200 hours. The selected adhesive 30 may be furthercapable of holding the lens 16 in position after a selected time periodexposed to a selected temperature of −40 degrees Celsius. The fullycured adhesive 30 may have other performance characteristics including:maintaining at least 70% of its strength (e.g. tensile strength) duringexposure to temperatures ranging from −40 degrees Celsius to 95 degreesCelsius, having a tensile strength of at least 1000 psi, having a ShoreD hardness value of at least 50, having a viscosity of between about30000 and 70000 centipoise, being non-hygroscopic (so that it does notswell significantly when exposed to moisture), having a cure depth of atleast 3 mm, having the capability to bond to PolybutyleneTerephtalate/Polycarbonate and/or Polyphenylene Sulfide and/or liquidcrystal polymer and/or anodized aluminum, having a bond shear strengthof at least 1000 psi with less than a 60% reduction in its bond shearstrength at 85 degrees Celsius, little or no outgassing, being capableof withstanding exposure to salt fog, being capable of withstandingtypical automotive chemicals, such as gasoline and automotive cleaningagents, having a glass transition temperature that is at least 90degrees Celsius and being ‘automotive-grade’ (i.e. being generallyapplicable for use in a vehicle).

The adhesive 30 may be applied by the robot itself prior to adjustmentof the lens 16 relative to the lens holder/front camera housing 14.Alternatively, the adhesive 30 may be applied by some other device priorto (or during) possession of the camera 10 by the robot.

Aside from fixing the position of the lens 16 relative to the lensholder/front camera housing 14, the adhesive 30 may also hermeticallyseal the interior of the camera 10 against the outside environment.

Numerous adhesives were attempted for use as the adhesive 30. Forexample, it was found that some adhesives, such as some UV-cure freeradical acrylates that have the capability of being initially curedusing UV light, have a reduced strength (e.g. tensile strength) underexposure to elevated operating temperatures such as 85 degrees Celsiusover a selected period of time. It was further found that adhesives,such as some UV-curable free radical epoxy hybrids also have a reducedstrength (e.g. tensile strength) under exposure to elevated operatingtemperatures such as 85 degrees Celsius over a selected period of time.Some cationic epoxies that were tried also lost their strength whenexposed to a temperature of 85 degrees Celsius and a humidity of 85%over a selected period of time. Some anionic cyanoacrylates that weretried were unsuitable as they produced too much outgas for optical use.Other adhesives, such as some UV-cure free radical silicones have arelatively low dimensional stability and are thus not suitable.

Surprisingly, it was found that a suitable adhesive that can be used forthe adhesive is adhesive AD VE 43812 manufactured by Delo IndustrialAdhesives of Windach, Germany. This adhesive is a low-temperature cure,epoxy-amine adhesive that can be cured initially relatively quickly byexposure UV light.

FIG. 3 shows a variant 100 of the rear view camera 10. This embodimentincorporates a lens 112, a front housing/lens holder 130, a back housing132 and an imager 140. As shown in greater detail in FIG. 4, the lens112 includes a lens barrel 114 in which lens optical elements 120,O-ring 122, spacers 124 and IR cutoff filter 126 are mounted and held inplace by a retainer cap 116. The front housing 130 holds the lens barrel114 via a threaded connection, or an adhesive flange as discussed above.A printed circuit board (PCB) 138 with imager 140 is mounted in thehousing defined by the front and back housing parts 130, 132. Screws 134are used for this purpose. In order to mount the lens 112, it is firstpositioned in the housing 130, 132 by a robot or multi-axis focusingmachine (not shown) so as to provide a focused image relative to theimager 140 and once properly aligned the lens 112 is thereafter fixedlyattached to the front housing 130. The sealing between the lens 112 andfront housing 130 is preferably provided by the adhesive discussedabove, or by utilizing a thread lock device. Then, the back housing 132is attached to the front housing 130 by laser or ultrasonic welding,adhesive, or via a press fitting.

Embodiment 2 Integration of Lens Barrel and Camera Lens Holder

FIG. 5 shows another embodiment 110 of a vehicular camera, wherein thelens barrel 114 housing the optical components of the lens 112 and thecamera front housing 130 form a single integrated piece 150. The lensoptical elements 120, O-rings and spacers 122, 124 and IR cutoff filter126 (FIG. 4) are placed inside a lens barrel portion 114′ of theintegrated lens barrel and camera upper housing piece 150 as part of theconventional lens assembly process to provide a lens 112′ (FIG. 5). Theintegrated piece 150 can be formed by plastic injection molding or metalmachining. Plastic injection molding is preferred for lower cost andease of attaching the back housing 132 to the integrated piece 150 bygluing, laser or ultrasonic welding.

The PCB 138 with imager 140 is mounted to the integrated piece 110. Lens112′ is focused relative to the imager 140 by applying techniquesdescribed in embodiments 3 to 6.

The advantages of this embodiment 110 include a savings in tooling costas one expensive upper housing plastic molding tool is eliminated;material cost savings since less plastic material is used and noexpensive adhesive or thread lock epoxy is needed; and a more simplifiedcamera assembly process since the step of attaching the lens to theupper housing is eliminated.

Embodiment 3 Lens Barrel Dropped on Surface of Imager

FIG. 6 shows another embodiment 200 of a vehicular camera wherein thelens barrel 114′ of the integrated piece 150 is dropped onto and sitsdirectly on top of the surface of the imager 140. During the cameraassembly process, the lens barrel 114′ is dropped directly onto theimager 140 as shown in FIG. 6. The lens barrel 114′ includes a specialdesigned mechanical feature such as rebate 202 (see detail view of FIG.6A) so that, while the lens barrel 114′ is dropped to onto the imager140, the rebate 202 guides the lens 112′ to have proper horizontalalignment such that the lens optical axis is in line with the center ofthe imager sensing area.

(The alignment of optics axis to the center of the imager can also beachieved by digital shifting of image sensing window on imager. Thisdigital center shifting feature can be found in some imagers, e.g.Aptina MT9V126 CMOS imager.)

As shown in FIG. 6, the lens 112′ can be secured by applying adhesive204 (such as UV-cured adhesive) around the interface of the lens barrel114′ with the imager 140 and PCB 138, thus fixing the lens focusposition. In a variant 200′ shown in FIG. 7, an alternative way to fixthe lens 112′ to the imager 140 is to include metal insert pins 206 inthe lens barrel 114′. The metal insert 206 is then soldered to the PCB138 during PCB reflow process to fix the lens 112′ to the PCB 138.

As shown in FIG. 8, the distance from the lens principal plane LPP tothe lens seating surface H1 (which is defined by a cover glass 158 thatis spaced apart from imaging sensor surface 160), and the distance H2between the imaging sensor surface 160 to the top surface of cover glass158 need to satisfy the relation H1+H2=F+ΔF, where F is the effectivefocal length of the lens, and ΔF is the focus tolerance range.

ΔF multiplied by two (ΔF*2) is also called depth of focus, which canrange from a few micrometers to hundreds of micrometers. For a typicalautomotive camera, the depth of focus is about 40 to 70 micrometers. H1and H2 are the two sources that contribute to the variation of focus.The lens barrel 114′ may be designed to have a tightly controlled lengthtolerance. The barrel length can be designed such that when it isdropped on the imager cover glass 158, the lens is focused right to theimager sensing surface 160 nominally. The imager 140 can also bedesigned such that the distance H2 between the sensing surface 160 andthe top cover glass surface of the imager has a tight tolerance.However, the lenses and imagers manufactured will always have variationsfrom their designed nominal values. The variation of H1 and H2 can stackup and drive the lens imager pair out of focus.

To control the focus tolerance and increase manufacturing yield, one ormore of the following methods can be employed:

First, use optical technology such as wavefront coding as promoted byOmniVision. The technology uses specially designed lens elements andimage processing algorithm to increase the depth of focus (ΔF) of thelens. The wider lens depth of focus allows more tolerate of focusposition variation. The manufacturing yield and product focus qualitycan be maintained high.

Second, use a laser or other means to cut or ablate extra lens barrelmaterial in the bottom of the lens barrel 114′ so that the correct lensbarrel length can be altered to achieve good focus. A pre-laser ablationfocus measurement is performed to determine how much barrel material toablate. To address the case that the lens being too short, one candesign the lens barrel so that it is always in the longer side.

Third, bin and match lens 112′ and imager 140 to achieve good drop-onfocus. The idea is to measure and sort lenses and imagers. Bin thelenses and imagers to matching groups. For example, a lens group withPlus 20 to 30 micrometer too long of flange focal length is matched withan imager group with Minus 20 to 30 micrometer too short of silicon totop glass distance. The two groups will form a good focus camera.

It will thus be seen that by directly dropping the lens 112′ to theimage sensor 140, it is possible to avoid a time-consuming assembly stepin the camera manufacturing process which requires actively searchingfor best focus position. It results in a reduced cycling time andincreased production efficiency, and avoids the use of a very expensivemulti-axis focus machine.

Embodiment 4 Lens Focus by PCB Mounting and Focusing Screws

FIG. 9 shows another embodiment 300 of a vehicular camera where a camerafront housing 330 includes a mechanical guidance feature such as wall302 for guiding the lens 112 to proper horizontal alignment with theimager 140 so that the lens optical axis is in line with the center ofthe imager sensing surface. In this embodiment, the PCB 138 with imager140 is attached to the front housing 330 by screws 304 but alsoutilizing compressive gaskets, wave washers or lock washers 306 heldbetween the PCB 138 and body of the front housing 330. The focusingbetween the lens 112 to imager 140 is accomplished by turning thesescrews 304 and actively monitoring camera output.

The alignment of the lens optical axis and imager center can be achievedby digitally shift the image window on the imager.

Referring additionally to FIG. 10, the attachment of the camera backhousing 132 to the front housing 330 (not drawn in this drawing) can beachieved by laser or ultrasonic welding, glue, press fitting, screwtogether or other means.

The camera front housing in this embodiment may also employ anintegrated lens barrel as discussed in with reference to embodiment 110.

Embodiment 5 Lens Focused by Positioning of Camera Front and BackHousings

FIG. 11 shows another embodiment 400 of a vehicular camera in which theintegrated lens barrel and camera upper housing piece 150 of embodiment110 is attached to the camera back housing 132 by UV cured glue 402. Theglue is applied before focus. An active focus and alignment (utilizing amulti-axis focusing machine) is performed to reach optimum lens focusand optical axis alignment to the imager center. While holding theintegrated lens barrel and camera front housing piece 150 in theposition achieving the best focus and alignment, a robot applies UVillumination to the adhesive to cure it and fix the position of the lens112′ and seal the camera. In this embodiment, the PCB 138 is mounted toback housing by screws 134, glue between PCB and back housing or othermeans.

In a variant 400′ shown in FIG. 12, the UV cured adhesive 402′ alsoreplaces the screws 134 used to mount the PCB 138 to the housing. Theadhesive 402′ thus attaches the PCB 132 to the back housing 138, fixesthe integrated piece 150 to the back housing 132, and seals the camera.

In another variant 400″ shown in FIG. 13, the imager PCB is focused andaligned and then fixed to the lens barrel and camera front housing piece150 by UV cured adhesive 402″ applied on and between the PCB 138 andstandoff parts 404″ of the integrated piece 150. During the focusassembly process, the imager PCB 138 is grabbed and moved in x, y and zdirection(s), and optionally in two rotational directions, to achieveoptimum focus and alignment. While the imager PCB 138 is being held inthe position, UV illumination is applied to cure the adhesive 402″.

Embodiment 6 Direct Attachment of Lens and Imager by Adhesive

FIG. 14 shows another embodiment 500 of a vehicular camera in whichtransparent UV-curable adhesive 502 is applied directly between lens 112and imager 140 and/or PCB 138. The adhesive 502 is provided as arelatively large blob to bonds the lens 112 to the imager 140 and/or thePCB 138. The focus and alignment of the lens 112 is performed before UVlight cures the adhesive. The adhesive preferably encapsulates theimager 140 and acts a protective shield for it.

In a preferred method of assembly, adhesive is applied on and around theimager in a controlled amount. A 5-axis robot (not shown, with motionsin x, y, z and two orthogonal rotations) also grips and dips the lensinto a batch of adhesive. The robot then focuses and aligns the lens tothe imager, whereupon UV light is applied to cure the adhesive. Therobot then releases the lens.

This embodiment simplifies the lens barrel design and reduces the lenssize. This embodiment can also be more advantageous than embodimentsthat utilize a threaded lens, which can be slow to focus or difficult tohold, or a press-fit lens, which provides only coarse movement and thuscan be difficult to control. Thus, a more accurate alignment can beobtained.

In all of the foregoing embodiments it is also desired to reduce thecost of the lens itself. This can be accomplished in one or more of thefollowing ways.

First plastic may be used for the lens barrel 114 and retainer cap 116.The barrel and cap are preferably made by injection molding of plasticmaterial like PPS. This material is dense, nonporous, rigid and hasultra-low hygroscopic characteristics and thus it meets the specialenvironmental and durability requirements for a rear view camera lens.

Second, the lens 112′ may be formed to incorporate only one glasselement as the outer-most element 120 a (FIG. 4) of the lens, andutilize two or three plastics lens (made by injection molding) for theinner optical elements. An alternative configuration may include twoglass elements and one or two plastic lenses. Minimizing the number ofglass elements reduces cost of the optical components.

In addition, cost savings can be realized by eliminating the lens IRcutoff filter 126 which is conventionally provided as a glass plate.Instead, the IR cutoff filter can be moved to the imager cover glass 120a. One added benefit of eliminating the IR cutoff filter in the lens isthat it reduces or eliminate light multi-reflection between the flat IRcutoff filter and imager cover glass 120 a. This multi-reflection cancause lens flare and ghost images.

Third, lens cost can be reduced by lowering the lens resolution. Thelens resolution can be reduced to a level that fits the applicationrequirement of the camera. More particularly, the human eye resolutionperception can be represented by a contrast sensitivity function (CSF)as shown in FIG. 15. The CSF peaks within a range of 1 to eight cyclesper degree, where a cycle is defined as a one transition from black towhite (or vice versa), which may be referred to in the literature as a“line pair”. Thus, a required resolution can be determined from thedisplay size, the distance between the observer and the display, theselected CSF, and the size of the imager sensing surface.

For example, consider a 7-inch diagonal display (with a 16×9) aspectratio. It has a horizontal dimension of 155 mm. Assume the distancebetween the observer and the display is 600 mm, which is the averagedistance between a driver's eyes and a display in the vehicle centerconsole. Select a CSF of 7 cycles per degree, which is a reasonablecompromise between machine vision and human vision requirements. Andassume that the imager has a horizontal sensing width of 3.58 mm. Oneangular degree represents a width of 10.5 mm at distance of 600 mm. Thedisplay resolution required is 0.67 line pairs/mm. The required cameraresolution is thus 28.9 line pairs per mm. Thus, a camera can produce asufficient resolution is its lens yields a camera level modulationtransfer function of 28.9 line pairs per mm.

Other examples of sufficient camera resolutions are provided in thechart below:

Display diagonal size (inch) 8 7 6 3.5 2.5 Aspect Ratio 16 × 9 16 × 9 16× 9 4 × 3 4 × 3 Horizontal Dimension 177 155 133 71.1 50.8 (mm) Eye toDisplay Distance 600 600 600 500 500 (mm) mm per 1 degree at 10.5 10.510.5 8.7 8.7 Display At display resolution 0.668 0.668 0.668 0.802 0.802(lp/mm) Required camera 33.0 28.9 24.8 15.9 11.4 resolution (lp/mm)

Thus, lens resolution can be reduced to the limits dictated by the CSFin order to reduce cost. Prior art lenses may have too high resolutionfor human visual perception, and high resolution lenses can adverselycause a negative consequence called the “Moire Effect”. Some of priorart camera designs utilized an optical low pass filter to lower theimage sharpness of the lens to eliminate the “Moire Effect”. The opticallow pass filter adds cost to camera along with the higher cost highresolution lens.

Fourth, lens cost can be reduced by not optically addressing anychromatic aberration in lens. Lens chromatic aberration can cause theresultant image to have color fringes at the edges of objects, as wellas lower image resolution. Lens chromatic aberration can typically befixed or mitigated by a pair of glass lens cemented together, theso-called achromat pair. However, for a low cost lens solution, thechromatic aberration is not fixed in the lens, rather, the imagersystem-on-chip (SOC) or an adjunct digital processor applies digitalcorrection to correct the chromatic aberration. The chromatic aberrationtypically has fixed amount of spatial separation among different colorsat a specific off-axis angle, as shown in the lateral color diagramexample of FIG. 16.

The basic principle of digital correction of chromatic aberration is asfollows.

Every pixel of an imager has individual values of red, green and bluecolors. By shifting one pixel colors to one or more other pixels, andrepeat the process to the whole imager, it is possible to correct orreduce the effect of lens chromatic aberration. Based on the lateralcolor separation of the lens, like the example graph shown in FIG. 16,the separation of the color as a function of the distance from thecenter of the imager is known. For each imager pixel, it is possible tocalculate the distance needed to shift every individual colors of thepixel. The shift happens in a radial direction because of the lens'symmetry to its axis. In each pixel, new position coordinates of eachcolor is re-calculated. Then this color value will be sent to the newpixel whose coordinates were calculated. The other two colors of thispixel are also calculated and sent to new pixels.

This shifting or redistribution of the pixel colors can be performed inSystem-On-Chip (SOC) part of imager, or a separate processor after theimager. The processor can be a microprocessor, a DSP, or a FPGA or otherdigital devices. Adding some gates or logical units to an existingdigital processing unit most likely is less expensive than addingachromat glass elements in lenses. The lens chromatic aberration istypically symmetric over the optical axis, which lowers the complexityof digital chromatic aberration in the SOC or processor.

Lens manufacturing variation may cause the chromatic aberration to notbe totally cylindrically symmetric. The spectral response of everyimager pixel may thus have variations. To correct the negative effect todigital chromatic aberration caused by these two variations, one canapply calibration procedures. During a calibration procedure, a specialtarget, an image acquisition and image processing algorithms are used tocalculate lateral color separation at every pixel. Then the pixelrelated lateral color values are used in digital chromatic aberrationcorrection process described above.

While the above describes particular embodiment(s) of the invention, itwill be appreciated that modifications and variations may be made to thedetailed embodiment(s) described herein without departing from thespirit of the invention.

1. A process for providing a vehicular camera suitable for vehicularuse, said process comprising: providing a front camera housing having alens assembly disposed thereat; said lens assembly including lensoptics; providing an imager disposed on a printed circuit board;disposing an adhesive in its uncured state between said front camerahousing and said printed circuit board; adjusting said front camerahousing and said printed circuit board relative to each other to achieveoptical center-alignment and focusing of said lens optics relative tosaid imager; wherein optical center-alignment and focusing of said lensoptics relative to said imager is achieved via a multi-axis positioningdevice; initially curing the adhesive from its uncured state to aninitially-cured state in an initial radiation curing process thatcomprises exposure to UV light for a first time period; further curingthe adhesive from the initially-cured state to a further more curedstate in a secondary curing process undertaken for a second time period;wherein said second time period is longer than said first time period;wherein the adhesive is initially cured from its uncured state to theinitially-cured state via the initial radiation curing process aftersaid lens optics is brought into focus with said imager and is opticallycenter-aligned therewith; wherein the adhesive, as cured to theinitially-cured state via the initial radiation curing process, (i)attaches said printed circuit board to said front camera housing and(ii) holds said lens optics optically center-aligned and in focus withsaid imager; and after the initial radiation curing process iscompleted, moving said front camera housing, with said printed circuitboard adhesively attached thereto, to the secondary curing process andfurther curing the adhesive to the further more cured state.
 2. Theprocess of claim 1, wherein the secondary curing process comprises atleast one of (i) thermal cure, (ii) moisture cure and (iii) radiationcure.
 3. The process of claim 1, wherein said first time period is sevenseconds or less.
 4. The process of claim 3, wherein said second timeperiod is greater than seven seconds.
 5. The process of claim 4, whereinsaid second time period is greater than twenty five seconds.
 6. Theprocess of claim 1, comprising joining a rear camera housing to saidfront camera housing to substantially encase said printed circuit board,and wherein said rear camera housing comprises an electrical connectorfor electrically connecting circuitry associated with operation of saidvehicular camera to electrical wiring of a vehicle.
 7. The process ofclaim 6, wherein said rear camera housing is joined to said front camerahousing via at least one of (i) ultrasonic welding, (ii) adhesive and(iii) press fitting.
 8. The process of claim 1, wherein, when more curedvia the secondary curing process, the adhesive, in the further morecured state, maintains focus and optical center-alignment of said lensoptics with said imager for use of said vehicular camera on a vehicle.9. The process of claim 8, wherein, with said printed circuit boardattached to said front camera housing by the adhesive in the furthercured state, at least a minimum strength of bond exists between saidprinted circuit board and said front camera housing after being exposedto a temperature of approximately 85 degrees Celsius and a humidity ofapproximately 85% for 1000 hours.
 10. The process of claim 1, whereinsaid lens assembly comprises a lens barrel, said lens barrel includingsaid lens optics, and wherein said lens assembly secures to said frontcamera housing by at least one of (i) mechanical attachment, (ii)threaded connection and (iii) a cured adhesive.
 11. The process of claim1, wherein at least one of (a) a lens resolution of said lens optics isselected to meet but not substantially exceed a resolution determinedfrom at least one of (i) the size of a display associated with saidvehicular camera when said vehicular camera is mounted on a vehicleequipped with said vision system, (ii) a distance between an observerand a display associated with said vehicular camera when said vehicularcamera is mounted on a vehicle equipped with said vision system, (iii) aselected point on a contrast sensitivity function and (iv) the size ofthe imager sensing surface, and (b) said lens optics omits achromaticlenses and employs digital chromatic correction based on a predeterminedchromatic aberration measurement.
 12. The process of claim 1, whereinsaid multi-axis positioning device comprises a multi-axis robot andwherein optical center-alignment and focusing of said lens opticsrelative to said imager is achieved robotically.
 13. The process ofclaim 1, wherein the adhesive, as disposed in its uncured state betweensaid printed circuit board and said front camera housing, has athickness of up to approximately 0.75 mm.
 14. The process of claim 1,wherein, when the adhesive is in the initially-cured state, a gap existsbetween the end of said lens optics and said imager.
 15. The process ofclaim 14, wherein the gap is devoid of the adhesive.
 16. The process ofclaim 1, wherein said lens assembly comprises a lens barrel, said lensbarrel including said lens optics.
 17. The process of claim 16, whereinsaid lens optics comprises a plurality of optical elements.
 18. Theprocess of claim 17, wherein said front camera housing comprises acylindrical opening and wherein said lens barrel is at least partiallyreceived in said cylindrical opening of said front camera housing. 19.The process of claim 1, wherein said vehicular camera is configured foruse as a rearward viewing camera of a vehicle.
 20. A vehicular cameraprovided in accordance with the process of claim
 1. 21. A process forproviding a vehicular camera suitable for vehicular use, said processcomprising: providing a front camera housing having a lens assemblydisposed thereat; said lens assembly including lens optics; providing animager disposed on a printed circuit board; disposing an adhesive in itsuncured state between said front camera housing and said printed circuitboard; adjusting said front camera housing and said printed circuitboard relative to each other to achieve optical center-alignment andfocusing of said lens optics relative to said imager; wherein opticalcenter-alignment and focusing of said lens optics relative to saidimager is achieved via a multi-axis positioning device; initially curingthe adhesive from its uncured state to an initially-cured state in aninitial radiation curing process that comprises exposure to UV light fora first time period; further curing the adhesive from theinitially-cured state to a further more cured state in a secondarycuring process undertaken for a second time period; wherein said secondtime period is longer than said first time period; wherein the adhesiveis initially cured from its uncured state to the initially-cured statevia the initial radiation curing process after said lens optics isbrought into focus with said imager and is optically center-alignedtherewith; wherein the adhesive, as cured to the initially-cured statevia the initial radiation curing process, (i) attaches said printedcircuit board to said front camera housing and (ii) holds said lensoptics optically center-aligned and in focus with said imager; after theinitial radiation curing process is completed, moving said front camerahousing, with said printed circuit board adhesively attached thereto, tothe secondary curing process and further curing the adhesive to thefurther more cured state; and wherein at least one of (i) saidmulti-axis positioning device comprises a multi-axis robot and saidoptical center-alignment and focusing of said lens optics relative tosaid imager is achieved robotically, (ii) the adhesive, as disposed inits uncured state between said printed circuit board and said frontcamera housing, has a thickness of up to approximately 0.75 mm and (iii)when the adhesive is cured, a gap exists between the end of said lensoptics and said imager.
 22. The process of claim 21, wherein, when theadhesive is in the initially-cured state, a gap exists between the endof said lens optics and said imager, and wherein the gap is devoid ofthe adhesive.
 23. The process of claim 22, wherein said lens assemblycomprises a lens barrel, said lens barrel including said lens optics,and wherein said lens optics comprises a plurality of optical elements,and wherein said front camera housing comprises a cylindrical openingand wherein said lens barrel is at least partially received in saidcylindrical opening of said front camera housing.
 24. The process ofclaim 23, wherein said multi-axis positioning device comprises amulti-axis robot and wherein optical center-alignment and focusing ofsaid lens optics relative to said imager is achieved robotically. 25.The process of claim 24, wherein said first time period is seven secondsor less.
 26. The process of claim 25, wherein said vehicular camera isconfigured for use as a rearward viewing camera of a vehicle.
 27. Theprocess of claim 21, wherein, when more cured via the secondary curingprocess, the adhesive, in the further more cured state, maintains focusand optical center-alignment of said lens optics with said imager foruse of said vehicular camera on a vehicle.
 28. The process of claim 27,wherein, with said printed circuit board attached to said front camerahousing by the adhesive in the further cured state, at least a minimumstrength of bond exists between said printed circuit board and saidfront camera housing after being exposed to a temperature ofapproximately 85 degrees Celsius and a humidity of approximately 85% for1000 hours.
 29. A vehicular camera provided in accordance with theprocess of claim
 21. 30. A process for providing a vehicular camerasuitable for vehicular use, said process comprising: providing a frontcamera housing having a lens assembly disposed thereat; said lensassembly including lens optics; providing an imager disposed on aprinted circuit board; disposing an adhesive in its uncured statebetween said front camera housing and said printed circuit board;adjusting said front camera housing and said printed circuit boardrelative to each other to achieve optical center-alignment and focusingof said lens optics relative to said imager; wherein opticalcenter-alignment and focusing of said lens optics relative to saidimager is achieved via a multi-axis positioning device; initially curingthe adhesive from its uncured state to an initially-cured state in aninitial radiation curing process that comprises exposure to UV light fora first time period; further curing the adhesive from theinitially-cured state to a further more cured state in a secondarycuring process undertaken for a second time period; wherein said firsttime period is seven seconds or less; wherein said second time period islonger than said first time period; wherein the adhesive is initiallycured from its uncured state to the initially-cured state via theinitial radiation curing process after said lens optics is brought intofocus with said imager and is optically center-aligned therewith;wherein the adhesive, as cured to the initially-cured state via theinitial radiation curing process, (i) attaches said printed circuitboard to said front camera housing and (ii) holds said lens opticsoptically center-aligned and in focus with said imager; after theinitial radiation curing process is completed, moving said front camerahousing, with said printed circuit board adhesively attached thereto, tothe secondary curing process and further curing the adhesive to thefurther more cured state; wherein said multi-axis positioning devicecomprises a multi-axis robot and wherein optical center-alignment andfocusing of said lens optics relative to said imager is achievedrobotically; and wherein, when the adhesive is in the initially-curedstate, a gap exists between the end of said lens optics and said imager.31. The process of claim 30, wherein the gap is devoid of the adhesive.32. The process of claim 31, wherein the adhesive, as disposed in itsuncured state between said printed circuit board and said front camerahousing, has a thickness of up to approximately 0.75 mm.
 33. The processof claim 31, wherein said vehicular camera is configured for use as arearward viewing camera of a vehicle.
 34. The process of claim 33,wherein said multi-axis positioning device comprises a multi-axis robotand wherein optical center-alignment and focusing of said lens opticsrelative to said imager is achieved robotically.
 35. The process ofclaim 34, wherein, when more cured via the secondary curing process, theadhesive, in the further more cured state, maintains focus and opticalcenter-alignment of said lens optics with said imager for use of saidvehicular camera on a vehicle.
 36. The process of claim 35, wherein,with said printed circuit board attached to said front camera housing bythe adhesive in the further cured state, at least a minimum strength ofbond exists between said printed circuit board and said front camerahousing after being exposed to a temperature of approximately 85 degreesCelsius and a humidity of approximately 85% for 1000 hours.
 37. Avehicular camera provided in accordance with the process of claim 30.38. A process for providing a vehicular camera suitable for vehicularuse, said process comprising: providing a front camera housing having alens assembly disposed thereat; said lens assembly including lensoptics; said front camera housing comprising a cylindrical opening;wherein said lens barrel is at least partially received in saidcylindrical opening of said front camera housing; providing a printedcircuit board; wherein an imager is disposed on said printed circuitboard; disposing an adhesive in its uncured state between said printedcircuit board and said front camera housing; adjusting said lensassembly relative to said front camera housing to achieve opticalcenter-alignment and focusing of said lens optics relative to saidimager; wherein optical center-alignment and focusing of said lensoptics relative to said imager is achieved via a multi-axis positioningdevice; initially curing the adhesive from its uncured state to aninitially-cured state in an initial radiation curing process thatcomprises exposure to UV light for a first time period; further curingthe adhesive from the initially-cured state to a further more curedstate in a secondary curing process undertaken for a second time period;wherein said second time period is longer than said first time period;wherein the adhesive is initially cured from its uncured state to theinitially-cured state via the initial radiation curing process aftersaid lens optics is brought into focus with said imager and is opticallycenter-aligned therewith; wherein the adhesive, as cured to theinitially-cured state via the initial radiation curing process, (i)attaches said printed circuit board to said front camera housing and(ii) holds said lens optics optically center-aligned and in focus withsaid imager; after the initial radiation curing process is completed,moving said front camera housing, with said printed circuit boardadhesively attached thereto, to the secondary curing process and furthercuring the adhesive to the further more cured state; wherein, when morecured via the secondary curing process, the adhesive, in the furthermore cured state, maintains focus and optical center-alignment of saidlens optics with said imager for use of said vehicular camera on avehicle; and wherein, when the adhesive is in the initially-cured state,a gap exists between the end of said lens optics and said imager andwherein the gap is devoid of the adhesive.
 39. The process of claim 38,wherein the secondary curing process comprises at least one of (i)thermal cure, (ii) moisture cure and (iii) radiation cure.
 40. Theprocess of claim 39, comprising joining a rear camera housing to saidfront camera housing to substantially encase said printed circuit board,and wherein said rear camera housing comprises an electrical connectorfor electrically connecting circuitry associated with operation of saidvehicular camera to electrical wiring of a vehicle.
 41. The process ofclaim 39, wherein said lens assembly comprises a lens barrel, said lensbarrel including said lens optics, and wherein said lens opticscomprises a plurality of optical elements, and wherein said front camerahousing comprises a cylindrical opening and wherein said lens barrel isat least partially received in said cylindrical opening of said frontcamera housing.
 42. The process of claim 41, wherein said multi-axispositioning device comprises a multi-axis robot and wherein opticalcenter-alignment and focusing of said lens optics relative to saidimager is achieved robotically.
 43. A vehicular camera provided inaccordance with the process of claim
 38. 44. A process for providing avehicular camera suitable for vehicular use, said process comprising:providing a front camera housing having a lens assembly disposedthereat; said lens assembly including lens optics; providing an imagerdisposed on a printed circuit board; disposing an adhesive in itsuncured state between said front camera housing and said printed circuitboard; adjusting said front camera housing and said printed circuitboard relative to each other to achieve optical center-alignment andfocusing of said lens optics relative to said imager; wherein opticalcenter-alignment and focusing of said lens optics relative to saidimager is achieved via a multi-axis positioning device; initially curingthe adhesive from its uncured state to an initially-cured state in aninitial radiation curing process that comprises exposure to UV light fora first time period; further curing the adhesive from theinitially-cured state to a further more cured state in a secondarycuring process undertaken for a second time period; wherein said secondtime period is longer than said first time period; wherein the adhesiveis initially cured from its uncured state to the initially-cured statevia the initial radiation curing process after said lens optics isbrought into focus with said imager and is optically center-alignedtherewith; wherein the adhesive, as cured to the initially-cured statevia the initial radiation curing process, (i) attaches said printedcircuit board to said front camera housing and (ii) holds said lensoptics optically center-aligned and in focus with said imager; after theinitial radiation curing process is completed, moving said front camerahousing, with said printed circuit board adhesively attached thereto, tothe secondary curing process and further curing the adhesive to thefurther more cured state; wherein, when the adhesive is in theinitially-cured state, a gap exists between the end of said lens opticsand said imager and wherein the gap is devoid of the adhesive; andjoining a rear camera housing to said front camera housing tosubstantially encase said printed circuit board.
 45. The process ofclaim 44, wherein said vehicular camera is configured for use as arearward viewing camera of a vehicle.
 46. The process of claim 45,wherein said rear camera housing comprises an electrical connector forelectrically connecting circuitry associated with operation of saidvehicular camera to electrical wiring of a vehicle.
 47. The process ofclaim 45, wherein said lens assembly comprises a lens barrel, said lensbarrel including said lens optics, and wherein said lens assemblysecures to said front camera housing by at least one of (i) mechanicalattachment, (ii) threaded connection and (iii) a cured adhesive.
 48. Theprocess of claim 47, wherein the secondary curing process comprises atleast one of (i) thermal cure, (ii) moisture cure and (iii) radiationcure.
 49. The process of claim 48, wherein said lens assembly comprisesa lens barrel, said lens barrel including said lens optics, and whereinsaid lens optics comprises a plurality of optical elements, and whereinsaid front camera housing comprises a cylindrical opening and whereinsaid lens barrel is at least partially received in said cylindricalopening of said front camera housing.
 50. The process of claim 44,wherein said multi-axis positioning device comprises a multi-axis robotand wherein optical center-alignment and focusing of said lens opticsrelative to said imager is achieved robotically.
 51. The process ofclaim 50, wherein, when more cured via the secondary curing process, theadhesive, in the further more cured state, maintains focus and opticalcenter-alignment of said lens optics with said imager for use of saidvehicular camera on a vehicle.
 52. The process of claim 51, wherein,with said printed circuit board attached to said front camera housing bythe adhesive in the further cured state, at least a minimum strength ofbond exists between said printed circuit board and said front camerahousing after being exposed to a temperature of approximately 85 degreesCelsius and a humidity of approximately 85% for 1000 hours.
 53. Avehicular camera provided in accordance with the process of claim 44.54. A process for providing a vehicular camera suitable for vehicularuse, said process comprising: providing a front camera housing;providing a lens assembly including lens optics; providing an imagerdisposed on a printed circuit board; attaching said printed circuitboard to said front camera housing; disposing an adhesive in its uncuredstate between said front camera housing and a portion of said lensassembly; adjusting said front camera housing and said lens assemblyrelative to each other to achieve optical center-alignment and focusingof said lens optics relative to said imager; wherein opticalcenter-alignment and focusing of said lens optics relative to saidimager is achieved via a multi-axis positioning device; initially curingthe adhesive from its uncured state to an initially-cured state in aninitial radiation curing process that comprises exposure to UV light fora first time period; further curing the adhesive from theinitially-cured state to a further more cured state in a secondarycuring process undertaken for a second time period; wherein said secondtime period is longer than said first time period; wherein the adhesiveis initially cured from its uncured state to the initially-cured statevia the initial radiation curing process after said lens optics isbrought into focus with said imager and is optically center-alignedtherewith; wherein the adhesive, as cured to the initially-cured statevia the initial radiation curing process, (i) attaches said lensassembly to said front camera housing and (ii) holds said lens opticsoptically center-aligned and in focus with said imager; after theinitial radiation curing process is completed, moving said front camerahousing, with said lens assembly adhesively attached thereto, to thesecondary curing process and curing the adhesive to the further morecured state; and wherein, when the adhesive is in the initially-curedstate, a gap exists between the end of said lens optics and said imager,and wherein the gap is devoid of the adhesive.
 55. The process of claim54, wherein said lens assembly comprises a lens barrel, said lens barrelincluding said lens optics, and wherein said lens optics comprises aplurality of optical elements, and wherein said front camera housingcomprises a cylindrical opening and wherein said lens barrel is at leastpartially received in said cylindrical opening of said front camerahousing.
 56. The process of claim 54, wherein said multi-axispositioning device comprises a multi-axis robot and wherein opticalcenter-alignment and focusing of said lens optics relative to saidimager is achieved robotically.
 57. The process of claim 56, whereinsaid first time period is seven seconds or less.
 58. The process ofclaim 57, wherein, when more cured via the secondary curing process, theadhesive, in the further more cured state, maintains focus and opticalcenter-alignment of said lens optics with said imager for use of saidvehicular camera on a vehicle.
 59. The process of claim 57, wherein,with said lens assembly attached to said front camera housing by theadhesive in the further cured state, at least a minimum strength of bondexists between said printed circuit board and said front camera housingafter being exposed to a temperature of approximately 85 degrees Celsiusand a humidity of approximately 85% for 1000 hours.
 60. The process ofclaim 54, comprising joining a rear camera housing to said front camerahousing to substantially encase said printed circuit board.
 61. Theprocess of claim 60, wherein said vehicular camera is configured for useas a rearward viewing camera of a vehicle.
 62. The process of claim 61,wherein said rear camera housing comprises an electrical connector forelectrically connecting circuitry associated with operation of saidvehicular camera to electrical wiring of a vehicle.
 63. The process ofclaim 54, wherein the adhesive, as disposed in its uncured state betweensaid lens assembly and said front camera housing, has a thickness of upto approximately 0.75 mm.
 64. A vehicular camera provided in accordancewith the process of claim 54.